In regard to liquid packaging containers for medical use, for example, infusion solution bags, bags made of glass or bags made of plastic have been used. The liquid medicine injected into the infusion solution bag is sealed, and then is generally sterilized according to methods such as steam sterilization and autoclave sterilization. Since infusion solution bags made of glass have a problem that these bags are heavier than the bags made of plastic and are susceptible to damage when subjected to impact, dropping or the like at the time of transportation, infusion solution bags made of plastic are widely used.
Regarding the infusion solution bags made of plastic, a bag made of a soft vinyl chloride resin, or a bag made of a polyolefin such as polyethylene or polypropylene is used. Since an infusion solution bag made of a soft vinyl chloride resin contains a large amount of a plasticizer in order to impart flexibility to the bag, there is a risk that depending on the kind of the infusion solution, the plasticizer may be eluted out into the infusion solution, and this has been pointed out with regard to the aspect of safety. Furthermore, since medical instruments are disposable, infusion solution bags made of a soft vinyl chloride resin are also incinerated after use. However, there is a problem that toxic gases attributable to the soft vinyl chloride resin are generated. Furthermore, infusion solution bags made of a polyolefin such as polyethylene or polypropylene do not contain plasticizers, and therefore, these bags are preferable with regard to the aspect of hygiene. However, since these infusion solution bags have low flexibility and insufficient impact resistance, it cannot be said that the bags are satisfactory in view of handleability.
On the other hand, for the purpose of improving flexibility, sealability and blocking resistance, a multilayer film for medical use, which uses a polypropylene-based resin composition including 50% by mass to 98% by mass of a crystalline polypropylene-based resin, 1% by mass to 49% by mass of a particular ethylene-α-olefin copolymer, and 1% by mass to 49% by mass of a particular hydrogenated block copolymer as a seal layer (inner layer), has been proposed (see PTL 1).